Dose counter with lockout mechanism

ABSTRACT

A medicament dispenser, in particular a metered dose inhaler, which is able to count the number of time the dispenser is activated and then disable the device, which then prevents any additional medicament from being dispensed. Additional embodiments include a medicament dispenser which are adapted to display either the number of activations that have occurred or the number of activations remaining.

This application is a continuation of U.S. patent application Ser. No.12/387,867, filed May 7, 2009 which claims priority under 35 U.S.C.§119(e) from U.S. Provisional Application Ser. No. 61/126,855, filed May7, 2008, which are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention described herein relates to the field of drugdelivery. More specifically, the present invention relates to an inhalerand a method for delivering doses of aerosolized medication forinhalation by a patient into the lungs which incorporates a dose countercomponent having a lockout feature and a method for counting the numberof drug doses in an inhaler and inactivating the inhaler, so that nomore drug can be delivered, when a predetermined number of doses havebeen delivered.

BACKGROUND OF THE INVENTION

Aerosols are increasingly being used for delivering medication fortherapeutic treatment of the lungs as well as systemic delivery oftherapeutic agents. For example, in the treatment of asthma, inhalersare commonly used for delivering bronchodilators such as β₂ agonists andanti-inflammatory agents such as corticosteroids. Two types of inhalersare in common use, pressurized metered dose inhalers (pMDIs) and drypowder inhalers (DPIs). Both types of inhalers have as their object thedelivery of medication (which is typically in the form of a solidparticulate or powder) into the airways of the lungs at the location ofthe condition being treated or for systemic delivery.

In a traditional pMDI device, the medication is provided in apressurized aerosol canister, with the medication being suspended ordissolved in a liquid propellant such as a chlorofluorocarbon (CFC) orhydrofluoroalkane (HFA). The canister includes a metering valve having ahollow discharge stem which can be depressed inward against an internalspring. Once the discharge stem is fully depressed into the canister ametered volume of propellant-medication mixture is discharged throughthe stem. The discharge is in the form of an aerosol comprising finedroplets of propellant in which particles of the medication aresuspended or dissolved. A typical pMDI for use with such a canisterincludes a housing having an actuator and a nozzle. The canister isinserted into the housing with the hollow discharge stem of the canisterbeing received in a bore in the actuator. Depressing the closed end ofthe canister causes the stem to be pushed inward into the canister sothat a metered volume of medication is discharged through the nozzle.The housing further defines a flowpath in fluid communication with thenozzle, with the flowpath having an outlet at a mouthpiece portion ofthe housing, such that the aerosolized medication may be inhaled afterit exits the mouthpiece portion. The patient either inserts themouthpiece into the mouth with the lips closed around the mouthpiece, orholds the mouthpiece at a slight distance away from an open mouth. Thepatient then depresses the canister to discharge the medication, andsimultaneously inhales.

In the field of inhalers, it is known to use a dose counter for trackingand/or displaying the number of doses that have been dispensed or thatremain to be dispensed from the inhaler. Such conventional counters aregenerally incremented each time a drug dose is expelled by the inhaler.

In addition, there exists a need to inactivate the inhaler in order toprevent a patient from delivering more than the required number ofdoses. For standard pills or tablets, only the actual number of dosesprescribed by the physician are dispensed by the pharmacist. For aninhaler the problem is far more complicated. It isn't practical to limitthe number of doses by limiting the amount of propellant/drug in thecanister because then the last few actuations of the inhaler would onlydeliver a partial dose. Thus there is a need to be to able to inactivatethe inhaler while there is still sufficient content in the canister toprovide for the full amount of drug delivery for each of the actuationsof the inhaler.

In addition it may be difficult from a manufacturing perspective toproperly fill the canister with a de minimus amount of medicament. Thusfrom a quality control perspective, it is better to fill the canisterwith an amount that permits reproducible filling and then limit thenumber of doses by use of the counter/lockout mechanism of the presentinvention.

The disclosed invention was developed to correct the above-describedproblem. The disclosed invention of a dose counter/lockout mechanism isshown incorporated into an inhaler having a pMDI medication canister, asynchronized breath-actuated trigger, and a flow control chamber.However, the disclosed dose counter/lockout mechanism could beincorporated into a inhaler in which the canister actuation is donemanually.

Furthermore, the disclosed inhaler includes a dose counter thatincrements only after an actual delivery of drug from the medicationcanister as occurs when the canister is depressed beyond a certainpoint. Upon reaching a predetermined number of actuations two thingsoccur. One is that the dose counting wheel can no longer be incremented.Secondly, a spring assembly, which needs to be cocked (i.e. compressed)in order to depress and therefore discharge medicament from thecanister, is disengaged from the rest of mechanism and therefore can'tbe compressed and therefore can't cause the medicament canister delivera dose.

BRIEF SUMMARY OF THE INVENTION

The present invention described herein involves an actuationcounter/lockout mechanism which disables a device after a predeterminednumber of mechanical actuations have occurred. Though described hereinas being a component of a pressurized metered dose inhaler, theinvention could be a component in any type of mechanical device whichcan cause a movable carriage to be translated. For example, the devicemight be used in conjunction with a device which delivers sugar pills toexperimental lab animals and would be deactivated after the animal hastriggered the device a predetermined number of times. The followingdescriptions, discussions and drawings will be directed to the inventionbeing incorporated into a specific class of device—that of a pMDI.However, it will be understood by one skilled in the art that this isonly one of many possible types of mechanical devices that couldincorporate the invention.

The present invention also includes a method for counting and displayingthe number of actuation cycles of a pMDI. Furthermore, the method mayinclude a deactivation step which prevents the inhaler from being ableto actuate the pMDI canister.

The foregoing and other features and advantages of the invention areapparent from the following detailed description of exemplaryembodiments, read in conjunction with the accompanying drawings. Thedetailed description and the drawings are merely illustrative of theinvention rather than limiting the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofpreferred embodiments of the invention, will be understood when read inconjunction with the appended drawings. For the purpose of illustratingthe invention, there is shown in the drawings embodiments which arepresently preferred. It should be understood, however, that theinvention is not limited to the precise arrangements and configurationsshown.

Figs. A-D depict in diagrammatic form the general operation of a priorart inhaler

Figs. E-H depict in diagrammatic form the dosage counter/lockoutinvention.

FIG. 1 is an external perspective view of one embodiment of the inhaler;

FIG. 2 is another external exploded perspective view of an embodiment ofthe inhaler;

FIG. 3 shows 4 perspective views of the Cradle of the present invention;

FIG. 3A is a perspective view of a pMDI canister disposed within theCradle of the present invention;

FIG. 3B is an exploded perspective view of the pMDI canister and Cradleshown in FIG. 3A;

FIG. 4 is a an exploded view of the Cradle and Manifold of the presentinvention;

FIG. 5 is an exploded perspective view of the Manifold showing severalof the breath actuation components;

FIG. 6 is an exploded perspective view of the Manifold and the CockingLever Retainer;

FIG. 6B shows Cocking Lever Retainer positioned on the Manifold;

FIG. 7 is an exploded perspective view of the Cocking Lever Retainer andthe Counter Wheel;

FIG. 8 is an alternative exploded perspective view of the Cocking LeverRetainer and the Counter Wheel;

FIG. 9 is an exploded view of the Spring Assembly;

FIG. 10 is a perspective view of internal Spring Assembly;

FIG. 11 is an alternate perspective view of Spring Assembly;

FIG. 12 is a perspective view of Spring Assembly disposed within theCradle;

FIG. 13 is a perspective view of the Cocking Lever;

FIG. 14 is an alternate perspective view of Cocking Lever;

FIG. 15 is a perspective view of Cocking Lever, Cradle and Cocking LeverRetainer; and

FIG. 16 is a cutaway view showing Cocking Lever in a partially elevatedposition.

I. DIAGRAMMATIC DEPICTION OF THE DOSAGE COUNTER-LOCKOUT

The diagrams shown in Figs. A-H are meant to provide a generalfunctional explanation of how the dosage counter/lockout feature works.Initially a description of the general operation of an inhaler withoutthe dosage counter/lockout mechanism is shown in Figs A-D and describedbelow. The reference numbers below for Figs. A-H, do not match thereference numbers used in FIGS. 1-16.

Fig. A: Cradle 53 holds the Canister 55 which has projecting from thecanister, a hollow spring loaded Canister Stem 57. Canister 55 ispressurized with a propellant containing a medicament, usually as asolution or a particulate suspension. When Canister Stem 57 is depressedand pushed against the spring pressure into the body of Canister 55, ameasured aliquot of the canister contents are expelled under pressure ofthe propellant out of the hollow Canister Stem 57 and into the inspiredairflow cause by the patient breathing in though the Inhaler Body 50.

Cradle 53 is rigidly attached to Spring Assembly 59. Cradle 53 isslideably attached to Inhaler 50 but limited in its downward directionvia Cradle Latch 52. Cradle Latch 52 can be deactivated by various meanswhich then allows Cradle 53 to slideably move along Inhaler Body 50.Cradle Latch 52 can be designed to uncouple in response to air flowthrough the Inhaler 50 caused by a patient breathing in through theInhaler Body 50. Instead of being breath actuated, Cradle Latch 52 canalternatively be designed to be activated manually which means thepatient must coordinate the inspiration of a breath with the manualactivation of Cradle Latch 52

Fig A depicts what is considered to be the Reset or Restingconfiguration. Cam 63 is pushing against Reset Arm 67 which is holdingCradle 53 and Spring Assembly 61 in the fully upward position such thatCradle Latch 52 can be positioned in the engaged position.

In Fig. B, Cam 63 has rotated such that it is now pushing on SpringAssembly 59. And because Spring Assembly 59 is fixedly attached toCradle 53, Cradle 53 is biased slightly downward and is held in place byCradle Latch 52. Because the Moving Assembly (Spring Assembly 59, Cradle53, and Canister 55) is held in position, the springs in Spring Assembly59 are compressed as shown by the box representing Spring Assembly 59being shown smaller in size.

Fig. C shows the configuration after a patient has actuated Cradle Latch52 either manually or by drawing in a breath which causes Cradle Latch52 to uncouple and allows the Moving Assembly to be biased downwards bythe expansion of the compressed springs.

Cradle 53 is configured to bias Canister 55 downwards which forcesCanister Stem 57 to be biased against Stem Retainer 54. As a result ofbeing biased against Stem Retainer 54, Canister Stem 57 is displacedinto Canister 55, which causes a measured aliquot of medicament to bedischarged from the canister as discussed above.

After the dose of Medicament 69 has been discharged, Cam 63 is rotatedback to the reset or rest position as shown in Fig. D. The lobe on Cam63 biases Reset Arm 67 upward, which in turn biases Moving Assembly backto its upward position. With the Moving Assembly located in its highestupward location, Cradle latch 52 is then automatically reset.

Now the device is ready for the next actuation cycle. In practice, Cam63 is attached to a Cocking Lever which also functions as mouthpiececover which is positioned in the closed position in Fig. A and Fig. D(Reset Position) and rotated to the open position in Fig. B (cockedposition) and Fig. C (discharged position).

When the patient picks up the inhaler, the cover is closed and allcomponents are as shown in Fig. A. The patient rotates the cover to thefully open position, which makes the inhaler available for use and whichrotates Cam 63 and configures the device as shown in Fig. B. With thecover open, the patient draws in a breath, actuates the breath actuatedtrigger which then allows the medicament to be dispensed into the airstream that is being drawn into the lungs by the patient. Duringmedicament delivery the Inhaler is in the configuration shown in Fig. C.

When the inhalation and medicament delivery are finished, the patientrotates the cover closed, which causes Cam 63 to be rotated back to itsreset position which places the device in the configuration shown inFig. D, which is in fact the same as Fig. A. When Cradle 53 is placed inthe upper position, by the rotation of Cam 63, pressure is removed fromCanister 55. The Canister Stem is then pushed back out by the action ofthe compressed spring(s) in Canister 55 which causes Canister 55 to moveback to its reset position.

II. DOSAGE COUNTER—DIAGRAMMATIC DEPICTION OF FIRST COMPONENT OF THEINVENTION

The additional inventive components of the dosage counter lock outfunctions are now discussed, building upon the description given above.

As shown in Fig. E, there are two additional components needed toeffectuate the Dosage Counter feature. A Counter Actuation Arm 72 isattached to Cradle 53. Each time that the Inhaler goes through theresetting function as described above for Fig. D, the Counter ActuationArm 72 pushes against one of a series of Notches 77 on the periphery ofthe Dosage Counter Wheel 75. On the periphery of the Dosage CounterWheel is imprinted a series of numbers (usually 1-4 or 1-8). Each timethe inhaler goes through the steps of medicament delivery, CounterActuation Arm causes the Dosages Counter Wheel to rotate a fixed amountwhich causes the next higher number on the Dosage Counter Wheel to bevisible through a window in the housing of the inhaler. The DosageCounter feature can be designed to either count up or count down asrequired.

Lock Out

There are two additional features needed to effectuate the lockoutfunction. Notches 77, which are described above, are located along onlya portion of the periphery of Counter Wheel 75. The Inhaler is designedto actuate only a predetermined number of times and the number ofNotches 77 is same as this predetermined number of actuations. Once theCounter Wheel has advanced this predetermined number of items, there areno more Notches on the wheel that the Contact Arm 72 can contact. ThusCounter Arm 72 has nothing to push against. So even if the Cradle 53moves back and forth between the positions shown in Fig. A and Fig. C,because the Contact Arm 72 is not making contact with any Notches 77,the Counter Wheel 75 doesn't rotate.

If no further components were added to the inhaler, the inhaler wouldstill be able to deliver medicament, but the counter wheel would onlyrecord a predetermined number of actuations.

There are additional elements needed, which would work in conjunctionwith the Counter Arm and Counter Wheel, to disable the inhaler. Withthese additional elements, when the Counter Wheel has been incrementallyrotated the predetermined number of times, the inhaler will be disabledand will not deliver medicament. The preferred method of disablement isto prevent the ability of the inhaler to compress the springs. It shouldbe noted that there is no physical blocking or interference of any ofthe moving parts while in the disabled state and therefore there are noparts put under stress when the inhaler is disabled.

A Dropout Cam 79 is located along the periphery of Counter Wheel 75.When Counter Wheel 75 has been incrementally rotated the proper numberof times, it is positioned such that Dropout Cam 79 makes contact withDropout Tab 81 which causes Spring Latch 83 to disengage as shown inFig. F.

Spring Latch 83, when engaged, rigidly attaches Cradle 53 to SpringAssembly 59. When Dropout Tab 81 is contacted by Dropout Cam 79, iscauses the two portions of Spring Latch 83 to separate. Thus SpringAssembly 59 is no longer rigidly attached to Cradle 53. As aconsequence, when Cam 63 rotates to the position as shown in Fig. G, thesprings in Spring Assembly 59 won't compress because the whole SpringAssembly moves in relation to Cradle 53. Therefore there won't be anymechanical force available to bias Cradle 53 and Canister 55 and causeCanister Stem 57 to be depressed into Canister 53 and thus there will beno medicament delivery.

Even if Cradle latch 52 is activated, as shown in Fig. G, there is nocompressed spring force to drive the Canister. When the Cam 63 isrotated back to its original position, the Moving Assembly is returnedto its initial position and Cradle Latch 52 is re-engaged.

Having gone through a diagrammatic depiction of the standard inhaler(Figs. A-D) and the improved inhaler having a dosage counter and lockoutmechanism (Figs E-F), a detailed description of the preferred embodimentwill now be presented.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows Inhaler 100 in its closed resting state. Back Cover 105 andFront Cover 115 provide the basic housing structure for Inhaler 100.Cocking Lever 110, attaches to Inhaler 100 and pivots around Pivot Point112. A Dosage Counter Display Window 120 is formed within Front Cover115. The actual number of dose that have been delivered is indicated bynumbers on a rotating surface that can be viewed through Dosage CounterDisplay Window 120, as will be discussed in detail below.

FIG. 2 is an exploded view of Inhaler 100. Front Cover 115 and BackCover 105 enclose Manifold Assembly 125. Mouth Piece 130 is insertedthrough an opening in the bottom of Front Cover 115 and makes a snap fitwithin an opening in the lower portion of Manifold Assembly 125. CockingLever 110, in its closed position, covers Mouth Piece 130. In normaluse, Cocking Lever 110 will be manually rotated approximately 135degrees which fully uncovers Mouthpiece 130 and enabling Mouthpiece 130to be inserted into the mouth of a patient.

FIG. 3 shows Cradle 140 from 4 different views in order that the variouscomponents of Cradle 140 can be properly viewed. A clear understandingof all of the functions of the Cradle 140 is critical to anunderstanding how all of the features of the invention work together.There are six separate functions that the Cradle 140 performs:

-   -   1. Holds the Canister;    -   2. Slideably engages the Manifold 170;    -   3. Provides one part of the latch to the Manifold;    -   4. Provides one part of a latch to the Spring Assembly;    -   5. Actuates the Dose Counter Wheel; and    -   6. Provides support for the Spring Assembly

These six functions are now discussed in detail.

1. Holds the Canister

-   -   The Canister 167 is retained within Canister Enclosure 160,        which also pushes down on the Canister 167 when the Cradle 140        is pushed down, in order to activate Canister Stem 168 (See        FIGS. 3A and 3B).

2. Slideably Engages the Manifold 170;

-   -   There is a pair of arms that extend away from the body of Cradle        140. Each of the arms contains a Slider Groove 145 which engages        with a corresponding mating part (the Cradle Rails 180) on        Manifold 170 (see FIG. 4).

3. Provides One Part of the Latch to the Manifold Assembly;

-   -   Cradle Latch A 155, shown in FIG. 3, along with Trigger Shelf        190 (See FIG. 5) forms Cradle Latch Assembly (not shown) which        detachably fixes Cradle 140 to Manifold 170. The second part of        Cradle Latch Assembly is Trigger Shelf 190, which is position        within Trigger Pocket 187 as shown in FIG. 5. Panel 185 is shown        detached from Manifold 170. Panel 185 is normally positioned        within Manifold 170 by positioning Attachment Bracket 188A        within Panel Pocket 188B. Panel 185 through various gaskets and        seals, not shown, can be biased at Flexible Location 186, and        displaced into Manifold 170 by utilizing a venturi effect caused        by the inspiration of air by the patient. If Panel 185 is biased        inwards by the intake of breath of a patient on the inhaler,        then Trigger Shelf 190 becomes disengaged from Cradle Latch A        155. This triggering action normally takes place after Spring        Assembly has been compressed. The disengagement of the Cradle        Latch Assembly then allows the Springs in the Spring Assembly to        expand, forcing Cradle 140 downward which also forces Canister        167 downward causing a single dose of medicament to be        discharged from Canister 167 through Canister Stem 168.

4. Provides One Part of Spring Assembly

-   -   Spring Assembly Latch A 157, as shown in FIG. 3 mates with a        corresponding component on the Spring Assembly 240 which will be        described below. The two components form Spring Assembly Latch        158, which is a key component of the lockout feature of the        present invention and will be discussed below.

5. Actuates the Dose Counter Wheel;

-   -   Counter Actuation Rod 150 extends from Cradle 140 and contacts        Counter Wheel 217, shown in FIG. 7. Each time the Cradle 140        (See FIG. 3) moves from its cocked position to its resting        position, the Counter Actuation Arm 50 makes contact with        notches on the periphery of Counter Wheel 217, causing it to        rotate a predefined amount.

6. Provides Support for the Spring Assembly

-   -   Spring Assembly 240 (shown alone in an expanded view in FIG. 9,        and in a front and back view in FIGS. 10 and 11) is contained        within Cradle 140 as shown in FIG. 12. As shown in FIG. 12,        Spring Assembly Latch B 257 of Spring Assembly 240 is detachably        engaged with Spring Assembly Latch A 157, which is part of        Cradle 140. When Spring Assembly 240 is biased in the downward        direction (as discussed below) the engaged Spring Assembly Latch        158 causes the downward force applied to the Spring Assembly to        be transmitted to Cradle 140.

FIG. 6 shows Cocking Lever Retainer 200 detached from Manifold Assembly125. It is normally positioned on Manifold 170 as shown in FIG. 6B.Locking Tangs 205 are inserted into Slots 195. When Cocking LeverRetainer 200 is fully inserted into Manifold 170, there are two CockingLever Apertures 197 formed which are used to retain Cocking Lever 110 aswill be discussed below.

FIG. 7 shows Cocking Lever Retainer 200 and Counter Wheel 217. CounterWheel 217 fits over and is retained by Counter Wheel Axle 215. CounterWheel Axle 215 is made up of two arms which are compressed. CounterWheel 217 is then positioned such that the compressed arms of CounterWheel Axle 215 are inserted through Mounting Hole 213 formed in themiddle of Counter Wheel 217. Once Counter Wheel Axle 215 is fullyinserted into and through Mounting Hole 213, the two arms are allowed toexpand, which rotatably locks Counter Wheel 217 on Counter Wheel Axle215. Counter Wheel 217 fits over Detent Arms 210 which are positioned tofit into Detent Teeth 230 as shown in FIG. 8. The interaction of DetentArms 210 and Detent Teeth 230 permit Counter Wheel 217 to rotate in onlyone direction and in fixed increments determined by the spacing ofDetent Teeth 230.

Also shown in FIG. 8 are Rotation Actuation Teeth 225. These teeth areengaged by Counter Actuation Rod 150, located on Cradle 140, each timeCradle 140 is placed in its resting position. The spacing of RotationActuation Teeth 225 and Dose Numbers 218 are designed so that eachmovement of the Counter Actuation Rod 150 causes the next higher dosagenumber on Counter Wheel 217 to be visible in Dosage Counter DisplayWindow 120.

Various views of Spring Assembly 240 are shown in FIGS. 9-11. The threemain elements of Spring Assembly 240 are the Pusher 245, the Springs 250and Spring Holder 255. An exploded view of Spring Assembly 240 is shownin FIG. 9.

FIG. 10 shows one view of the fully assembled Spring Assembly 240. Oneeach of Springs 250 are placed over one each of Pusher Arms 247. Thisassembly is placed within Spring Holder 255 such that Pusher RetainingTabs 260 are inserted through openings in the bottom of Spring Holder255. Once place through these holes, Pusher Retaining Tabs 260 lockPusher 247 within Spring Holder 255. The diameter of Springs 250 aresmaller than the holes in the bottom of Spring Holder 255. Therefore, ifPusher 245 is biased downwards, Pusher Arms 247 are extended through theholes in the bottom of Spring Holder 255. This causes Springs 250 to becompressed between the lower portion of Spring Holder 255 and the top ofPusher 245.

FIG. 11 shows the opposite side of the view shown in FIG. 10. DropoutTab 265, which is located on the Dropout Arm 262, is engaged by DropoutCam 220 on Counter Wheel 217 (FIG. 7). When Dropout Tab 265 is biased bycontact with Dropout Cam 220 it moves in the direction indicated byArrow A. This causes Spring Assembly Latch A 157 to disengage fromSpring Assembly Latch B 257.

When Spring Assembly Latch is engaged, any downward pressure on thePusher 245 causes Springs 250 to compress and also transmits thedownward pressure to Cradle 140. And because the Cradle Latch (CradleLatch A 155 and Trigger Shelf 190) is usually engaged, Cradle 140 isprevented from making any significant downward motion. Thus the downwardpressure on Pusher 245 results in the Cradle 140 being biased tightlyagainst the Cradle Latch and also results in the compression of Springs250.

However, when Spring Assembly Latch is disengaged, there can be nocompression of Springs 250, and the whole Spring Assembly 240 is moveddownward within Cradle 140, without imparting any downward force toCradle 140. When there is no compression of Springs 250, there is nocompression energy available to cause the downward motion of the Cradle140 and the Canister 167 to overcome the forced needed to move theCanister Stem 168 into the Canister 167.

FIG. 12 shows in detail the Spring Assembly 240 positioned within Cradle140 and with Spring Assembly Latch components (Spring Assembly Latch A157 and Spring Assembly Latch B 257) in is an engaged, but slightlyseparated position in order to better view these two components.Normally Spring Assembly Latch A 157 and Spring Assembly Latch B 257 arein direct contact, unless Dropout Cam 220 has engaged Dropout Tab 265 tocause the two components to disengage and to potentially slide past eachother.

FIG. 13 shows Cocking Lever 110 with its Cams 270 and its Pivot Bearings267 located at one end. Pivot Bearings 267 are pivotally retained withinthe Cocking Lever Apertures 197 formed by the Cocking Lever retainer andthe Cocking Lever Support Brackets 192.

FIG. 1 shows Cocking Lever 110 is its closed or resting position. FIG.15 also shows several of the components in the closed or restingpositions. When Cocking Lever 110 is in the closed position, Cams 270are oriented such that Reset Lobes 290 are located as shown in FIG. 15.In this position, Reset Lobes 290 are oriented upwards and directly incontact with Reset Cam Contact Surface 162. In this position, Cradle 140is biased in its uppermost position.

During normal operation, as Cocking Lever 110 is rotated away fromMouthpiece 130, Cams 270 are rotated which brings Compression Lobes 280into contact with Cam Contact Surface 246, which causes Pusher 245 tocompress Springs 250.

When Cocking Lever 110 is rotated to its fully opened position (about135 degrees), it brings the Stabilizing Surface 285 on Cam 270 in fullcontact with Cam Contact Surface 246. Because Stabilizing Surface 285 isflat, when it is in full contact with Cam Contact Surface 246, CockingLever 110 is stabilized it is fully open position which holds Springs250 in a compressed state.

Typically, the next step is to trigger Cradle Latch Assembly, whichdisengages Cradle Latch A 155 from Trigger Shelf 190. Cradle 140 is thenbiased by the expansion of Springs 250. The force of the expansion ofcompressed Springs 250 is sufficient to overcome the force on CanisterStem which biases Canister Stem 168 into Canister 167 to cause deliveryof a metered dose of medicament.

After the delivery, Cocking Lever 110 is rotated back to the closedposition which causes Reset Lobe 290 to be rotated against Reset ArmContact Surface 162 which returns Cradle 140 back to its normalposition. With Cradle 140 is its uppermost position, Cradle LatchAssembly reengages, causing Cradle 140 to be fixedly attached toManifold 170.

FIG. 16 shows a cutaway view of the Inhaler 100 with the Cocking Lever110 in a partially elevated position. Cam 270 is shown oriented suchthat Compression Lobe 280 is in contact with Cam Contact Surface 246. Inthis configuration Pusher 245 is biased in a downward direction whichresults in Springs 250 being partially compressed.

FIG. 16 also shows Spring Assembly Latch B 257 engaged with SpringAssembly Latch A 157. If Cocking Lever 110 were to be raised further,Stabilizing Surface 285 would be rotated so that it comes in contactwith Cam Contact Surface 246 and be held in a stabilized position.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. Therefore, the scope of the invention is notlimited to the exemplary embodiment described above. All changes ormodifications within the meaning and range of equivalents are intendedto be embraced herein.

Terms and phrases used in this document, and variations thereof, unlessotherwise expressly stated, should be construed as open ended as opposedto limiting. As examples of the foregoing: the term “including” shouldbe read as mean “including, without limitation” or the like; the term“example” is used to provide exemplary instances of the item indiscussion, not an exhaustive or limiting list thereof; and adjectivessuch as “conventional,” “traditional,” “normal,” “standard,” “known” andterms of similar meaning should not be construed as limiting the itemdescribed to a given time period or to an item available as of a giventime, but instead should be read to encompass conventional, traditional,normal, or standard technologies that may be available or known now orat any time in the future. Likewise, a group of items linked with theconjunction “and” should not be read as requiring that each and everyone of those items be present in the grouping, but rather should be readas “and/or” unless expressly stated otherwise. Similarly, a group ofitems linked with the conjunction “or” should not be read as requiringmutual exclusivity among that group, but rather should also be read as“and/or” unless expressly stated otherwise.

The presence of broadening words and phrases such as “one or more,” “atleast,” “but not limited to” or other like phrases in some instancesshall not be read to mean that the narrower case is intended or requiredin instances where such broadening phrases may be absent.

As used in this application, the articles “a” and “an” refer to one ormore than one (i.e., to at least one) of the grammatical objects of thearticle. By way of example, “an element” means one element or more thanone element.

What is claimed it:
 1. A metered dose inhaler comprising: a pressurizedcanister containing a medicament formulation, said canister furthercomprising a metering valve having a spring loaded valve stem; acanister holder which fixedly holds said canister; an inhaler body; saidcanister holder being slideably engaged with said inhaler body; saidcanister holder movable between a first and second position; acompression assembly slideably engaged with said canister holder; acompression assembly latch that detachably affixes said compressionassembly to said canister holder; said compression assembly latch havingan engaged configuration in which said compression assembly is fixedlyattached to said canister holder and a disengaged configuration in whichsaid compression assembly is slideably engaged with said canisterholder; a cradle latch; said cradle latch having an engagedconfiguration wherein said canister holder is restricted to said firstposition and a disengaged configuration wherein said canister holder isnot restricted in its movement along said inhaler body; said canisterholder further comprising a reset arm; a cam positioned between saidreset arm and said compression assembly; such that when said cam isoriented in a first position the cam lobe is biased against said resetarm and urges said canister holder in said first position; and when saidcam is oriented in a second position said cam lobe is biased againstsaid compression assembly which causes mechanical energy to be stored insaid compression assembly when said cradle latch and said compressionassembly latch are both in the engaged positions; a dose counter wheel;said dose counter wheel adapted to be detentably rotatable in onedirection; said canister holder further comprising an actuation armwhich engages with said dose counter wheel and causes said dose counterwheel to incrementally rotate each time said canister holder moves fromsaid second position to said first position; said dose counter wheeladapted to display a different dose indicia each time said dose counterwheel is incrementally rotated and wherein said dose counter wheelcomprises a dropout cam; said dropout cam adapted to cause saidcompression assembly latch to disengage after a predetermined number ofincremental rotated and wherein said dose counter wheel comprises adropout cam; said dropout cam adapted to cause said compression assemblylatch to disengage after a predetermined number of incremental rotationswhich results in said dose counter wheel being in a predeterminedposition; whereby said compression assembly can no longer be compressedby said cam, thereby preventing storage of mechanical energy needed tomove canister holder from the disengaged position to the engagedposition, thereby preventing further discharge of medicament.
 2. Ametered dose inhaler as described in claim 1 wherein said cradle latchis manually disengaged.
 3. A metered dose inhaler as described in claim1 wherein disengagement of said cradle latch is breath-actuated.
 4. Ametered dose inhaler as described in claim 1 further comprising a coverwhich rotates within said inhaler body, said cover further comprising acam.
 5. A metered does inhaler as described in claim 1 wherein saidcompression assembly comprises one or more springs.
 6. A metered doseinhaler as described in claim 1 wherein said compression assembly latchcomprises a first and second latching member, said first latching memberfixedly attached to said compression assembly and said second latchingmember fixedly attached to said canister holder, wherein at least onesaid latching members can be directly or indirectly physically displacedby said dropout cam so that said compression assembly and said canisterholder are not fixedly attached to each other.
 7. A metered dose inhaleras described in claim 1 wherein said dose counter wheel has numbers onthe periphery of said dose counter wheel; said inhaler adapted toindicate a specific number as the number of interest.
 8. A metered doseinhaler as described in claim 7 wherein said inhaler is adapted to allowonly one of the numbers on the periphery of the dose counter wheel to bevisible from outside of said inhaler body.
 9. A medicament dispensercomprising: a medicament formulation; a medicament storage container;said medicament formulation contained within said medicament storagecontainer; a medicament dispersal unit which, when activated causes saidmedicament formulation to be dispersed from said medicament storageunit; a dose counter wheel; said dose counter wheel adapted to bedetentably rotatable in one direction, and wherein said dose counterwheel can be incrementally rotated each time for a predetermined numberof incremental rotations and wherein said dose counter wheel comprises adropout cam; an actuation arm which engages said dose counter wheel andcause said dose counter wheel to be incrementally rotated each time saidmedicament dispersal unit is activated, wherein after the predeterminednumber of incremental rotations have passed, the dropout cam is adaptedto prevent said medicament dispersal unit from being activated.
 10. Amedicament dispenser as described in claim 9 further comprising dosecounting indicia disposed on said dose counter wheel.
 11. A medicamentdispense as described in claim 10 wherein said dose counting indicia arenumbers.
 12. A medicament dispenser as described in claim 11 whereinonly one said numbers, at any one time, is visible from outside of saidmedicament dispenser.